Question

Q3.Draw an octagon and draw the diagonals . Count and verify the number of diagonals it has.​

Answer 1

Answer: 20

Step-by-step explanation:

5 + 5 + 4 + 3 + 2 + 1 = 20 unique diagonals.

Answer 2

Answer:

From a vertex you can draw 7 lines to the other vertices. Two of them are sides, 5 are diagonals.

So at first glance it looks like 40 diagonals — BUT each has been drawn twice (AC and CA, etc)

Answer: 20 diagonals.